1. Field of the Invention
The present invention relates to an optical disc recording technique, and more particularly, to a technique for reducing cross erasure in an optical disc recording apparatus by controlling the laser power during rewriting in a land/groove recording and reproducing technique.
2. Description of the Related Art
An optical disc, used as a noncontact information recording medium in an optical disc player, has been developed for high capacity, high speed, and high density recording with advancements in the information field. In particular, an optical disc capable of recording/reproducing high density information, such as a digital versatile disc (DVD), a random access memory (RAM), etc., has been actively developed in association with the recording/reproduction of image information in a multimedia PC or a high quality TV. Thus, a high-density optical disc medium having an improved capacity must be developed to handle the next generation multimedia market.
The recording density per unit area must be increased to manufacture a high-density optical disc. The recording density can be increased by reducing the size of a laser spot. The size of the laser spot is proportional to the wavelength .lambda. of a light beam and inversely proportional to the numerical aperture. Hence, in order to reduce the size of the laser spot, the wavelength of the beam must be reduced, or an objective lens having a high numerical aperture must be used.
The interval between the tracks of a high-density optical disc is gradually decreasing through the use of these methods.
An optical disc capable of recording information on lands and grooves formed thereon has already been proposed as an alternative to increasing the recording density within a limited recording area on an optical disc.
Typically, such an optical disc has a plurality of tracks formed from the inner circumference toward the edge of the disc in a spiral. Grooves are formed to predetermined depths on each track, and lands are formed to the surface height of the disc thereon. These lands and grooves alternate between adjacent tracks. A mark representing data information is formed on the lands and grooves by the power of a laser corresponding to a recording pulse pattern.
In a disc drive using this high-density optical disc as a recording medium, a recording pulse pattern depending on the recording states of nonoverwritten and overwritten tracks is represented as a record peak power and an erase power. However, for such a recording pattern, all domains with recording and erasing power are heated during overwriting. Thus, in the case of the land/groove recording method, e.g., when data is recorded in the grooves, cross erasure occurs, in which data recorded between adjacent lands is erased by generated heat, even in the recording section of a portion where nonoverwritten and overwritten erasing areas overlap each other. Therefore, the reliability of data between adjacent tracks is degraded.